Dkim C# Reference Documentation

Dkim

DomainKeys API for creating and verifying DKIM-Signature and DomainKey-Signature MIME (email) header fields. This API is included with the "Chilkat MIME" license. ("Chilkat MIME" may be referred to as "Chilkat S/MIME" on some chilkatsoft.com web pages. They are the same product.)

Object Creation

Chilkat.Dkim obj = new Chilkat.Dkim();

Properties

public bool AbortCurrent {get; set; }

Introduced in version 9.5.0.58

When set to true, causes the currently running method to abort. Methods that always finish quickly (i.e.have no length file operations or network communications) are not affected. If no method is running, then this property is automatically reset to false when the next method is called. When the abort occurs, this property is reset to false. Both synchronous and asynchronous method calls can be aborted. (A synchronous method call could be aborted by setting this property from a separate thread.)

public string DebugLogFilePath {get; set; }

If set to a file path, causes each Chilkat method or property call to automatically append it's LastErrorText to the specified log file. The information is appended such that if a hang or crash occurs, it is possible to see the context in which the problem occurred, as well as a history of all Chilkat calls up to the point of the problem. The VerboseLogging property can be set to provide more detailed information.

This property is typically used for debugging the rare cases where a Chilkat method call hangs or generates an exception that halts program execution (i.e. crashes). A hang or crash should generally never happen. The typical causes of a hang are:

  1. a timeout related property was set to 0 to explicitly indicate that an infinite timeout is desired,
  2. the hang is actually a hang within an event callback (i.e. it is a hang within the application code), or
  3. there is an internal problem (bug) in the Chilkat code that causes the hang.

public string DkimAlg {get; set; }

The signing algorithm to be used in creating the DKIM-Signature. Possible values are "rsa-sha256" and "rsa-sha1". The default value is "rsa-sha256".

public int DkimBodyLengthCount {get; set; }

Optional body length count to set a maximum number of body bytes to be hashed when creating the DKIM-Signature field. The default value is 0, indicating that the entire body should be hashed.

public string DkimCanon {get; set; }

Canonicalization algorithm to be used for both header and body when creating the DKIM-Signature. Possible values are "simple" and "relaxed". The default value is "relaxed".

public string DkimDomain {get; set; }

The domain name of the signing domain when creating the DKIM-Signature.

public string DkimHeaders {get; set; }

A colon-separated list of header field names that identify headers presented to the signing algorithm when creating the DKIM-Signature. The default value is: "mime-version:date:message-id:subject:from:to:content-type".

public string DkimSelector {get; set; }

The selector to be used to form the DNS query for the public key. This property applies to creating a DKIM-Signature. For example, if the selector is "reykjavik" and the domain is "example-code.com", then the DNS query would be for "reykjavik._domainkey.example-code.com".

public string DomainKeyAlg {get; set; }

The signing algorithm to be used in creating the DomainKey-Signature. The only possible value is "rsa-sha1". The default value is "rsa-sha1".

public string DomainKeyCanon {get; set; }

Canonicalization algorithm to be used for when creating the DomainKey-Signature. Possible values are "simple" and "nofws". The default value is "nofws".

public string DomainKeyDomain {get; set; }

The domain name of the signing domain when creating the DomainKey-Signature.

public string DomainKeyHeaders {get; set; }

A colon-separated list of header field names that identify headers presented to the signing algorithm when creating the DomainKey-Signature. The default value is: "mime-version:date:message-id:subject:from:to:content-type".

public string DomainKeySelector {get; set; }

The selector to be used to form the DNS query for the public key. This property applies to creating a DomainKey-Signature. For example, if the selector is "reykjavik" and the domain is "example-code.com", then the DNS query would be for "reykjavik._domainkey.example-code.com".

public int HeartbeatMs {get; set; }

The number of milliseconds between each AbortCheck event callback. The AbortCheck callback allows an application to abort any method call prior to completion. If HeartbeatMs is 0 (the default), no AbortCheck event callbacks will fire.

public string LastErrorHtml {get; }

Provides information in HTML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

public string LastErrorText {get; }

Provides information in plain-text format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

Concept of LastErrorText

LastErrorText Standard Information

public string LastErrorXml {get; }

Provides information in XML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

public bool LastMethodSuccess {get; set; }

Introduced in version 9.5.0.52

Indicate whether the last method call succeeded or failed. A value of true indicates success, a value of false indicates failure. This property is automatically set for method calls. It is not modified by property accesses. The property is automatically set to indicate success for the following types of method calls:

  • Any method that returns a string.
  • Any method returning a Chilkat object, binary bytes, or a date/time.
  • Any method returning a standard boolean status value where success = true and failure = false.
  • Any method returning an integer where failure is defined by a return value less than zero.

Note: Methods that do not fit the above requirements will always set this property equal to true. For example, a method that returns no value (such as a "void" in C++) will technically always succeed.

public bool VerboseLogging {get; set; }

If set to true, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is false. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.

public string Version {get; }

Version of the component/library, such as "9.5.0.63"

Methods

public byte[] AddDkimSignature(byte[] mimeIn);

This method is deprecated. It will be removed in a future version.

Constructs and prepends a DKIM-Signature header to the MIME. Prior to calling this method, your program must set both the DkimDomain and DkimSelector properties, and it must load a private key by calling LoadDkimPk or LoadDkimPkFile.

Note: This method is deprecated. Use the DkimSign method instead.

Returns an empty byte array on failure

(C#) Add DKIM-Signature Header to MIME / Email

(Mono C#) Add DKIM-Signature Header to MIME / Email

(.NET Core C#) Add DKIM-Signature Header to MIME / Email

(PowerShell) Add DKIM-Signature Header to MIME / Email

(C#) Send DKIM Signed Email

(Mono C#) Send DKIM Signed Email

(.NET Core C#) Send DKIM Signed Email

(PowerShell) Send DKIM Signed Email

public byte[] AddDomainKeySignature(byte[] mimeIn);

This method is deprecated. It will be removed in a future version.

Constructs and prepends a DomainKey-Signature header to the MIME. Prior to calling this method, your program must set both the DomainKeyDomain and DomainKeySelector properties, and it must load a private key by calling LoadDomainKeyPk or LoadDomainKeyPkFile.

Note: This method is deprecated. Use the DomainKeySign method instead.

Returns an empty byte array on failure

(C#) Add DomainKey-Signature Header to MIME / Email

(Mono C#) Add DomainKey-Signature Header to MIME / Email

(.NET Core C#) Add DomainKey-Signature Header to MIME / Email

(PowerShell) Add DomainKey-Signature Header to MIME / Email

public bool DkimSign(BinData mimeData);

Introduced in version 9.5.0.71

Constructs and prepends a DKIM-Signature header to the MIME passed in mimeData. Prior to calling this method, your program must set both the DkimDomain and DkimSelector properties, and it must load a private key by calling SetDkimPrivateKey.

Returns true for success, false for failure.

public bool DkimVerify(int sigIndex, BinData mimeData);

Introduced in version 9.5.0.71

Verifies the Nth DKIM-Signature header in the mimeData. (In most cases, there is only one signature.) The 1st signature is at sigIndex 0.

Important: Many anti-virus programs, such as AVG, will modify the MIME of an email as it is received. This will cause DKIM signature verification to fail because the body of the MIME is modified.

Returns true for success, false for failure.

public bool DomainKeySign(BinData mimeData);

Introduced in version 9.5.0.71

Constructs and prepends a DomainKey-Signature header to the MIME passed in mimeData. Prior to calling this method, your program must set both the DomainKeyDomain and DomainKeySelector properties, and it must load a private key by calling SetDomainKeyPrivateKey.

Returns true for success, false for failure.

public bool DomainKeyVerify(int sigIndex, BinData mimeData);

Introduced in version 9.5.0.71

Verifies the Nth DomainKey-Signature header in the mimeData. (In most cases, there is only one signature.) The 1st signature is at sigIndex 0.

Important: Many anti-virus programs, such as AVG, will modify the MIME of an email as it is received. This will cause DomainKey signature verification to fail because the body of the MIME is modified.

Returns true for success, false for failure.

public bool LoadDkimPk(string privateKey, string optionalPassword);

This method is deprecated. It will be removed in a future version.

Loads an RSA private key to be used for creating a DKIM-Signature. Any valid RSA private key format that is not binary, such as PEM or XML, may be passed to this method. This method will automatically determine the format and parse it correctly. A password is only required if key is encrypted, such as for encrypted PEM.

Note: This method is deprecated. Use the SetDkimPrivateKey method instead.

Returns true for success, false for failure.

(C#) DKIM Signature using Windows Current User Certificate Store

(Mono C#) DKIM Signature using Windows Current User Certificate Store

(.NET Core C#) DKIM Signature using Windows Current User Certificate Store

(PowerShell) DKIM Signature using Windows Current User Certificate Store

public bool LoadDkimPkBytes(byte[] privateKeyDer, string optionalPassword);

This method is deprecated. It will be removed in a future version.

Loads an RSA private key to be used for creating a DKIM-Signature. Any valid RSA private key binary format, such as DER, may be passed to this method. This method will automatically determine the format and parse it correctly. A password is only required if key is encrypted.

Note: This method is deprecated. Use the SetDkimPrivateKey method instead.

Returns true for success, false for failure.

public bool LoadDkimPkFile(string privateKeyFilePath, string optionalPassword);

This method is deprecated. It will be removed in a future version.

Loads an RSA private key file to be used for creating a DKIM-Signature. The file name contains any valid RSA private key format, such as DER, PKCS8, PEM, XML, etc. This method will automatically determine the format and parse it correctly. A password is only required if key is encrypted, such as for encrypted PEM or encrypted PKCS8.

Note: This method is deprecated. Use the SetDkimPrivateKey method instead.

Returns true for success, false for failure.

public bool LoadDomainKeyPk(string privateKey, string optionalPassword);

This method is deprecated. It will be removed in a future version.

Loads an RSA private key to be used for creating a DomainKey-Signature. Any valid RSA private key format that is not binary, such as PEM or XML, may be passed to this method. This method will automatically determine the format and parse it correctly. A password is only required if key is encrypted, such as for encrypted PEM.

Note: This method is deprecated. Use the SetDomainKeyPrivateKey method instead.

Returns true for success, false for failure.

public bool LoadDomainKeyPkBytes(byte[] privateKeyDer, string optionalPassword);

This method is deprecated. It will be removed in a future version.

Loads an RSA private key to be used for creating a DomainKey-Signature. Any valid RSA private key binary format, such as DER, may be passed to this method. This method will automatically determine the format and parse it correctly. A password is only required if key is encrypted.

Note: This method is deprecated. Use the SetDomainKeyPrivateKey method instead.

Returns true for success, false for failure.

public bool LoadDomainKeyPkFile(string privateKeyFilePath, string optionalPassword);

This method is deprecated. It will be removed in a future version.

Loads an RSA private key file to be used for creating a DomainKey-Signature. The file name contains any valid RSA private key format, such as DER, PKCS8, PEM, XML, etc. This method will automatically determine the format and parse it correctly. A password is only required if key is encrypted, such as for encrypted PEM or encrypted PKCS8.

Note: This method is deprecated. Use the SetDomainKeyPrivateKey method instead.

Returns true for success, false for failure.

public bool LoadPublicKey(string selector, string domain, string publicKey);

Caches a public key to be used for verifying DKIM and DomainKey signatures for a given selector and domain. The publicKey is a string containing an RSA public key in any text format, such as XML, PEM, etc. This method will automatically detect the format and load the public key correctly. This method is useful for testing DKIM and DomainKey verification when your public key has not yet been installed in DNS.

Returns true for success, false for failure.

public bool LoadPublicKeyFile(string selector, string domain, string publicKeyFilepath);

Caches a public key to be used for verifying DKIM and DomainKey signatures for a given selector and domain. The publicKeyFilepath is a filepath of an RSA public key in any format. This method will automatically detect the format and load the public key correctly. This method is useful for testing DKIM and DomainKey verification when your public key has not yet been installed in DNS.

Returns true for success, false for failure.

public int NumDkimSignatures(byte[] mimeData);

Returns the number of DKIM-Signature header fields found in mimeData.

public int NumDomainKeySignatures(byte[] mimeData);

Returns the number of DomainKey-Signature header fields found in mimeData.

public bool PrefetchPublicKey(string selector, string domain);

Useful if your application is going to verify many emails from a single domain (or a few domains). This eliminates the need to do a DNS lookup to fetch the public key each time an email's DKIM or DomainKey signature is verified.

This method may be called multiple times -- once for each selector/domain to be pre-fetched. The verify methods (VerifyDkimSignature and VerifyDomainKeySignature) will use a pre-fetched key if the selector and domain match.

Returns true for success, false for failure.

public Task PrefetchPublicKeyAsync(string selector, string domain);

Creates an asynchronous task to call the PrefetchPublicKey method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns null on failure

(C#) How to Run an Asynchronous Task

(Mono C#) How to Run an Asynchronous Task

(.NET Core C#) How to Run an Asynchronous Task

(PowerShell) How to Run an Asynchronous Task

public bool SaveLastError(string path);

Saves the last-error information (the contents of LastErrorXml) to an XML formatted file.

Returns true for success, false for failure.

public bool SetDkimPrivateKey(PrivateKey privateKey);

Introduced in version 9.5.0.71

Sets the private key file to be used for creating a DKIM-Signature.

Returns true for success, false for failure.

public bool SetDomainKeyPrivateKey(PrivateKey privateKey);

Introduced in version 9.5.0.71

Sets the private key file to be used for creating a DomainKey-Signature.

Returns true for success, false for failure.

public bool UnlockComponent(string unlockCode);

Unlocks the component allowing for the full functionality to be used. If this method unexpectedly returns false, examine the contents of the LastErrorText property to determine the reason for failure.

Returns true for success, false for failure.

Diagnosing UnlockComponent Problems

UnlockComponent LastErrorText shows exact string passed to it.

Verify UnlockComponent Success w/ Purchased Unlock Code

LastErrorText Standard Information

public bool VerifyDkimSignature(int sigIndex, byte[] mimeData);

This method is deprecated. It will be removed in a future version.

Verifies the Nth DKIM-Signature header in the mimeData. (In most cases, there is only one signature.) The 1st signature is at sigIndex 0.

Important: Many anti-virus programs, such as AVG, will modify the MIME of an email as it is received. This will cause DKIM signature verification to fail because the body of the MIME is modified.

Note: This method is deprecated. Use the DkimVerify method instead.

Returns true for success, false for failure.

public Task VerifyDkimSignatureAsync(int sigIndex, byte[] mimeData);

This method is deprecated. It will be removed in a future version.

Creates an asynchronous task to call the VerifyDkimSignature method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns null on failure

(C#) How to Run an Asynchronous Task

(Mono C#) How to Run an Asynchronous Task

(.NET Core C#) How to Run an Asynchronous Task

(PowerShell) How to Run an Asynchronous Task

public bool VerifyDomainKeySignature(int sigIndex, byte[] mimeData);

This method is deprecated. It will be removed in a future version.

Verifies the Nth DomainKey-Signature header in the mimeData. (In most cases, there is only one signature.) The 1st signature is at sigIndex 0.

Important: Many anti-virus programs, such as AVG, will modify the MIME of an email as it is received. This will cause DomainKey signature verification to fail because the body of the MIME is modified.

Note: This method is deprecated. Use the DomainKeyVerify method instead.

Returns true for success, false for failure.

public Task VerifyDomainKeySignatureAsync(int sigIndex, byte[] mimeData);

This method is deprecated. It will be removed in a future version.

Creates an asynchronous task to call the VerifyDomainKeySignature method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns null on failure

(C#) How to Run an Asynchronous Task

(Mono C#) How to Run an Asynchronous Task

(.NET Core C#) How to Run an Asynchronous Task

(PowerShell) How to Run an Asynchronous Task

Events

public event AbortCheckEventHandler OnAbortCheck;

Provides the opportunity for a method call to be aborted. The AbortCheck event is fired periodically based on the value of the HeartbeatMs property. If HeartbeatMs is 0, then no AbortCheck events will fire. As an example, to fire 5 AbortCheck events per second, set the HeartbeatMs property equal to 200.

Chilkat .NET Event Implementation

Args are passed using Chilkat.AbortCheckEventArgs

Event callback implementation:

private void dkim_OnAbortCheck(object sender, Chilkat.AbortCheckEventArgs args)
	{
	    // application code goes here.
	}

To add an event handler:

Chilkat.Dkim dkim = new Chilkat.Dkim();
dkim.OnAbortCheck += dkim_OnAbortCheck;

Chilkat Mono/.NET Core Event Implementation

Event callback implementation:

private void handleAbortCheckEventHandler OnhandleAbortCheck
	{
	    // application code goes here.
	}

To add an event handler:

Chilkat.Dkim dkim = new Chilkat.Dkim();
// ...
Chilkat.Dkim.AbortCheck abortCheck = new Chilkat.Dkim.AbortCheck(handleAbortCheck);
dkim.setAbortCheckCb(abortCheck);

public event BinaryDataEventHandler OnBinaryData;

Binary data provided by certain methods.

Chilkat .NET Event Implementation

Args are passed using Chilkat.BinaryDataEventArgs

Event callback implementation:

private void dkim_OnBinaryData(object sender, Chilkat.BinaryDataEventArgs args)
	{
	    // application code goes here.
	}

To add an event handler:

Chilkat.Dkim dkim = new Chilkat.Dkim();
dkim.OnBinaryData += dkim_OnBinaryData;

Chilkat Mono/.NET Core Event Implementation

Event callback implementation:

private void handleBinaryDataEventHandler OnhandleBinaryData
	{
	    // application code goes here.
	}

To add an event handler:

Chilkat.Dkim dkim = new Chilkat.Dkim();
// ...
Chilkat.Dkim.BinaryData binaryData = new Chilkat.Dkim.BinaryData(handleBinaryData);
dkim.setBinaryDataCb(binaryData);

public event PercentDoneEventHandler OnPercentDone;

Provides the percentage completed for any method that involves network communications or time-consuming processing (assuming it is a method where a percentage completion can be measured). This event is only fired when it is possible to know a percentage completion, and when it makes sense to express the operation as a percentage completed. The pctDone argument will have a value from 1 to 100. For operations (Chilkat method calls) that complete very quickly, the number of PercentDone callbacks will vary, but the final callback should have a value of 100. For long running operations, no more than one callback per percentage point will occur (for example: 1, 2, 3, ... 98, 99, 100).

The PercentDone callback counts as an AbortCheck event. For method calls that complete quickly such that PercentDone events fire, it may be that AbortCheck events don't fire because the opportunity to abort is already provided in the PercentDone callback. For time consuming operations, where the amount of time between PercentDone callbacks are long, AbortCheck callbacks may be used to allow for the operation to be aborted in a more responsive manner.

The abort output argument provides a means for aborting the operation. Setting it to true will cause the method to abort and return a failed status (or whatever return value indicates failure).

Chilkat .NET Event Implementation

Args are passed using Chilkat.PercentDoneEventArgs

Event callback implementation:

private void dkim_OnPercentDone(object sender, Chilkat.PercentDoneEventArgs args)
	{
	    // application code goes here.
	}

To add an event handler:

Chilkat.Dkim dkim = new Chilkat.Dkim();
dkim.OnPercentDone += dkim_OnPercentDone;

Chilkat Mono/.NET Core Event Implementation

Event callback implementation:

private void handlePercentDoneEventHandler OnhandlePercentDone
	{
	    // application code goes here.
	}

To add an event handler:

Chilkat.Dkim dkim = new Chilkat.Dkim();
// ...
Chilkat.Dkim.PercentDone percentDone = new Chilkat.Dkim.PercentDone(handlePercentDone);
dkim.setPercentDoneCb(percentDone);

public event ProgressInfoEventHandler OnProgressInfo;

A general name/value event that provides information about what is happening during a method call. To find out what information is available, write code to handle this event and log the name/value pairs. Most are self-explanatory.

Chilkat .NET Event Implementation

Args are passed using Chilkat.ProgressInfoEventArgs

Event callback implementation:

private void dkim_OnProgressInfo(object sender, Chilkat.ProgressInfoEventArgs args)
	{
	    // application code goes here.
	}

To add an event handler:

Chilkat.Dkim dkim = new Chilkat.Dkim();
dkim.OnProgressInfo += dkim_OnProgressInfo;

Chilkat Mono/.NET Core Event Implementation

Event callback implementation:

private void handleProgressInfoEventHandler OnhandleProgressInfo
	{
	    // application code goes here.
	}

To add an event handler:

Chilkat.Dkim dkim = new Chilkat.Dkim();
// ...
Chilkat.Dkim.ProgressInfo progressInfo = new Chilkat.Dkim.ProgressInfo(handleProgressInfo);
dkim.setProgressInfoCb(progressInfo);

public event TaskCompletedEventHandler OnTaskCompleted;

Called in the background thread when an asynchronous task completes.

C# TaskCompleted Event Callback Example

Chilkat .NET Event Implementation

Args are passed using Chilkat.TaskCompletedEventArgs

Event callback implementation:

private void dkim_OnTaskCompleted(object sender, Chilkat.TaskCompletedEventArgs args)
	{
	    // application code goes here.
	}

To add an event handler:

Chilkat.Dkim dkim = new Chilkat.Dkim();
dkim.OnTaskCompleted += dkim_OnTaskCompleted;

Chilkat Mono/.NET Core Event Implementation

Event callback implementation:

private void handleTaskIdCompletedEventHandler OnhandleTaskIdCompleted
	{
	    // application code goes here.
	}

To add an event handler:

Chilkat.Dkim dkim = new Chilkat.Dkim();
// ...
Chilkat.Dkim.TaskIdCompleted taskIdCompleted = new Chilkat.Dkim.TaskIdCompleted(handleTaskIdCompleted);
dkim.setTaskIdCompletedCb(taskIdCompleted);

public event TextDataEventHandler OnTextData;

Text data provided by certain methods.

Chilkat .NET Event Implementation

Args are passed using Chilkat.TextDataEventArgs

Event callback implementation:

private void dkim_OnTextData(object sender, Chilkat.TextDataEventArgs args)
	{
	    // application code goes here.
	}

To add an event handler:

Chilkat.Dkim dkim = new Chilkat.Dkim();
dkim.OnTextData += dkim_OnTextData;

Chilkat Mono/.NET Core Event Implementation

Event callback implementation:

private void handleTextDataEventHandler OnhandleTextData
	{
	    // application code goes here.
	}

To add an event handler:

Chilkat.Dkim dkim = new Chilkat.Dkim();
// ...
Chilkat.Dkim.TextData textData = new Chilkat.Dkim.TextData(handleTextData);
dkim.setTextDataCb(textData);